DIAGNOSIS OF BASAL ANOMALIES OF THE TRANSVERSE SENSE
- Introduction
Basal anomalies of the transverse sense affect the maxilla and/or the mandible. There are two clinical forms:
Insufficient transverse growth (endognathia). In this case, we observe a maxillomandibular disharmony which can lead to a kinetic anomaly: mandibular laterodeviation. Excessive transverse growth is then referred to as maxillary and/or mandibular exognathia.
- DIAGNOSTIC ELEMENTS
They arise from:
The anamnesis
- Age
- Heredity
- Medical history: Trauma, childhood illness
- Dental history: caries, early extractions
- Distorting habits: digital or lingual or labial sucking
- Breathing problems: enlarged tonsils, adenoids
The clinical examination
An exo-oral examination allows the face to be observed (fig.1):
- The general craniofacial form
- The symmetry or not of the face/PSM
- The symmetry of the eyebrows and eyes
- The shape and width of the nostrils
- The shape of the zygomatic processes
- The relief of the cheeks
- Lip shape and symmetry/PSM
- The width of the jaw in the smile
- Chin position
Muscle palpation (lips, cheeks and masticatory muscles) and examination of the TMJs should also be performed.
DIAGNOSIS OF BASAL ANOMALIES OF THE TRANSVERSE SENSE
Fig.1 Frontal examination of the face (symmetry and length of the floors)
On intraoral examination, the following should be noted:
- The shape and size of the arches and their relationship (palatine vault, mandibular arch)
- Symmetry of the hemi-arcades/median raphe and the lower lingual and labial frenulum
- The presence of possible symmetrical or asymmetrical deformations or inclinations of the alveolar processes (alveolar compensation due to transverse non-concordance of the arches)
- The presence of dental anomalies of number, shape, and volume which may or may not overlap with skeletal anomalies
- Morphology and posture of the tongue: general shape, volume, position at rest and during swallowing, length of its frenulum
- The presence or absence of dysfunctions: oral breathing (low tongue, hypertrophic tonsils), atypical swallowing, chewing problems
- Occlusal relationships in the static and dynamic states: incisive, canine and molar occlusion, occlusion of the lateral sectors, continuity of the arches, closing path, incisal slope in propulsion and canine or group protection in laterality
Additional examinations
They allow the diagnosis to be refined:
- Front and profile photographs to take measurements based on the PSM: normally the half-faces are symmetrical/PSM
The horizontal lines are parallel to each other and perpendicular to the median sagittal plane:
- The ophriac line
- The bipupillary line
- The subnasal line
- The bicommissural line
- Casts allow a detailed examination of the separated and occluded arches (Spee curve, Wilson curve, V or U shape, etc.). It is also possible to take measurements in order to make an alveolar or bone diagnosis in the transverse direction: Pont, Château and Izard indices.
- X-rays also provide a great deal of information and allow the diagnosis to be further refined. In the transverse direction, the panoramic image informs us about the symmetry of the nasal and maxillomandibular structures, taking into account the median sagittal plane. The same is true for the teleradiography in frontal and axial incidence.
- CLINICAL FORMS OF BASAL ANOMALIES OF THE TRANSVERSE SENSE
MAXILLARY ENDOGNATHY
It is an insufficiency of development of the maxilla in the transverse direction with a normal inclination of the PM and M and often anterior crowding.
- a- Symmetrical maxillary endognathism
- Facial signs : There are few or no facial signs unless the abnormality is associated with other malocclusions.
- Occlusal signs:
- Unilateral crossbite (with mandibular lateral deviation) or bilateral crossbite without lateral deviation (bilateral linguocclusion in ICM)
- In temporary dentition (absence of Bogue diastemas)
- In mixed dentition, there is significant maxillary incisal crowding.
- The palatine vault is symmetrical and ogival.
- The Izard index is decreased
- The mandibular arch is normal
- The incisal midpoints (fig.2) coincide at rest and in ICM (in the absence of latero-deviation) and are deviated in the presence of a deviation of the closing path (fig.3) – The latero-deviation is inconstant
Fig.2 Coincidence of incisal media in ICM
DIAGNOSIS OF BASAL ANOMALIES OF THE TRANSVERSE SENSE
Fig.3 Non-coincidence of incisal points (mandibular lateral deviation)
Functional signs
– Lingual interposition between the arches during swallowing;
-Oral or mixed breathing due to obstruction of the upper or middle airways (low position of the tongue).
b- Asymmetric maxillary endognathism
Asymmetric maxillary endognathism is mainly found in cases of cleft lip and palate with an asymmetrical palatal vault and a unilateral crossbite (fig. 4) without mandibular lateral deviation (coincidence of the incisal points).
DIAGNOSIS OF BASAL ANOMALIES OF THE TRANSVERSE SENSE
Fig.4 Unilateral endoclusis without deviation of the incisive points
Etiological factors
- Heredity (neuro-muscular behavior)
- Genetic congenital malformation
- Lingual dysfunctions at rest (low tongue) and during swallowing/phonation functions
- Breathing problems: airway obstruction
- Chewing disorders
- Digital Suction
Differential diagnosis
- Maxillary endoalveolitis
- Mandibular exoalveolus or exognathia
C- Mandibular endognathism
This is an uncommon anomaly that corresponds more to a mandible of reduced volume and retroposition or to compensation for maxillary endognathism. The etiology may be linked to a high lingual posture.
D- Maxillary exognathia
It is an excess of development of the maxilla in the transverse direction.
Facial signs
- Wide face with tapering lower floor
- Prominent cheekbones
- Flat or concave profile
Occlusal signs
- Wide arcade
- Shallow Palace
- Vestibulo-version or palato-version of the lateral sectors
- Significant or even true supraclusion
- Mandible inscribed in the maxilla
Etiology
- Heredity
- Macroglossia, high position of the tongue
- Iatrogenic excessive expansion of the maxilla
Differential diagnosis
- Mandibular endognathism or endoalveolism
- Maxillary exoalveolism
e- Mandibular exognathism
This is a rare anomaly. The mandible is too wide in the transverse direction.
Etiology
Voluminous and low tongue.
Differential diagnosis
- Endoalveolus or upper endognathia
- Inferior exoalveolus
F- Mandibular laterognathia
Definition
It is a basal anomaly characterized by an asymmetry of shape of the mandible. It designates an asymmetrical structural deformation of the mandible which can be accompanied by a maxillary asymmetry, or even an asymmetry of the base of the skull.
Clinical features
- A unilateral reverse occlusion
- The incisal media are deviated in ICM and RC, the closing path is straight
- The progression is absent
- The aesthetic impact is significant (facial asymmetry)
- The median sagittal plane is deviated from the subnasal point
- On teleradiography: non-coincidence of the right and left hemimandibles
Etiological factors
- Hereditary and congenital origin
- Severe growth disorders of the mandible
- Joint pathologies
- Unilateral nerve and muscle damage
- Functional abnormalities
- Mandible injuries
Differential diagnosis
It is done with mandibular lateral deviation.
It is a kinetic anomaly due to an occlusal disorder with:
- Absence of harmony between the maxilla and the mandible (symmetrical or asymmetrical maxillary endognathia)
- Occlusion disorders (dental malpositions, DDM, premature contacts).
- Facial asymmetry in occlusion is not visible in physiological resting position
DIAGNOSIS OF BASAL ANOMALIES OF THE TRANSVERSE SENSE
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